Research is being conducted on an M2M communication service supporting data communication between devices when no human interaction exists or when human control is very restrictive. The M2M communication service is attracting attention in decreasing a cost of managing devices through automatic control and communication. More particularly, the M2M communication service is a technology applicable to fleet management for vehicles and articles mounted on the vehicles, smart metering, home automation, health care and the like, and the possibility of its utilization is being expected.
In an M2M communication system, a system designer should consider a case where only a restricted device receives specific data, unlike a terminal of a general communication system. For example, information provided by a specific utility company has to be received by only a device that joins a service of the specific utility company and performs smart metering. For another example, a health care device receives health care information from a health care server, thereby being capable of maintaining, the latest health care information. At this time, the health care information should be transmitted only to a device joining a corresponding service.
As described above, there occurs a situation of transmitting or receiving limited data according to terminal's purpose and use in an M2M communication system. At this time, when a plurality of terminals of the same kind exists, the terminals all receive the same data from an M2M server. In this case, multicast data transmission is expected to provide efficiency in which the plurality of terminals transmits the same data. Therefore, a way for securely transmitting corresponding data only to a limited plurality of terminals is needed.
Thus, a way of creating and maintaining a multicast data encryption key in an M2M communication system is needed.